High-performance MEMS RF Passive Components And Silicon Micromachined Technology

In this dissertation, we mainly study the 3-D micromachined process and research of key RF passive components. On the one hand, this technology is performed in RFIC for communication. The novel process could be compatible with CMOS process with low temperature. Moreover, the substrate effect is suppressed deeply to get high-performance inductors, transformers and tunable capacitors. On the other hand, a nano-precision XY-stage is designed and fabricated with trench-sidewall technology. Moreover, the XY-stage is performed on a sigle wafer instead of SOI wafer to reduce the cost of the fabrication.The concave-suspended inductors and transformers are performed with CMOS compatible process under a low temperature. The embedded structures facilitate the post-fabricated and package such as flip-chip. The suspended structures survive the 10000g shock. Moreover, 100g acceleration is sequentially applied to X, Y and Z axes by using ANSYS software. The deformation is an order lower than other robust suspended spiral inductor. In consequence, the 2.74nH inductor shows a high peak Q-factor of about 54 at 5.35GHz. The self-resonance frequency is over 15GHz. To my best knowledge, the available gain of the transformer is the highest among the reported paper as 0.89.Suspended tunable capacitors are performed by using low stress electroplating and isotropic release process. The tuning ratio is about 3.18:1, namely 218%, under 4V driving voltage. The Q factor is about 103 at 1 GHz. We also propose a rotational tunable capacitor to suppress the circumstance acceleration and vibration. The deformation under acceleration is two orders lower than the conventional MEMS comb tunable capacitor. The rotational structure keeps not only low driving voltage but robust structure.A XY-stage is fabricated with trench-sidewall process. The precision of the displacement is better than 18nm. Using the trench-sidewall technology, piezoresistive, capacitive sensing and electrostatic driving could be integrated on single wafer to reduce the cost.